A continuous and reliable power supply is necessary for almost all electronic devices. FIG. 1 shows a block diagram of an AC to DC power supply system in accordance with the prior art. As with most power supplies for electronic devices, it converts alternating current (AC) to direct current (DC) that is output 22 to the device. In this example, the AC input 10 will typically range from 90-264 Volts at a frequency of 50-60 Hz. Once the AC switch 12 is closed the AC power is applied to the AC to DC Power Supply 14. The power supply 14 includes a Bridge Rectifier 16 that converts the AC into a unidirectional current. The use of a bridge rectifier circuit is well known to one of ordinary skill in the art. The rectified output is then input into a Boost PFC (Power Factor Correction) Converter 18. The boost PFC converter maintains a constant DC bus voltage on its output while drawing input current that is in phase with the input voltage. The output of the boost PFC converter is 375 Volts DC in this example. Finally, the Line Isolated DC to DC converter 20 creates the necessary operating voltages for the electronic device. These voltages are delivered as the output of the power supply to the electronic device.
Prior Art solutions to provide a backup power source have involved the use of various sizes of batteries. However, these backups typically involve some type of interruption of the power supply while the backup battery is engaged. Additionally, most batteries cannot provide an adequate backup power supply for a necessary period of time without adding a great deal of weight to the system. Therefore, an efficient uninterruptible power supply is desired.